1. Field of the Invention
The present general inventive concept relates to a read/write (R/W) control apparatus and method of a disk drive, and more particularly, to an apparatus and method to retry a data read and write while changing a flying height of a magnetic head in a disk drive.
2. Description of the Related Art
Korean Patent Publication No. 10-2004-0025373 relates to a technique of controlling the variation of a flying height between a write head and a disk according to a write current or over-shoot of the write current.
A hard disk drive (HDD), which is a type of data storage medium, reproduces data written on a disk or writes data on the disk using a magnetic head. As the BPI (bit per inch), i.e., the write density in the disk rotational direction, and the TPI (track per inch), i.e., the write density in a radius direction of the disk, have increased, small-sized and high storage capacity HDDs can be manufactured. Accordingly, a more accurate positional mechanism for the HDD is needed.
A flying height of a magnetic head, which is a gap between the magnetic head and a disk in an HDD, affects read and write performance of the HDD. The read and write performance is more improved as the flying height of the magnetic head is lowered, however, the possibility of collision between the magnetic head and the disk becomes higher. On the contrary, the possibility of collision between the magnetic head and the disk can be reduced as the flying height of the magnetic head becomes higher, however, the read and write performance becomes more degraded.
Considering the above description, the flying height of the magnetic head is determined when the HDD is designed and is usually determined to be a fixed value. The flying height of the magnetic head varies according to user conditions such as ambient temperature, air pressure, and so on.
If an error occurs in a data read and write process, the HDD retries the data read and write process until no error occurs while varying designed parameter values by predetermined times.
According to the prior art, when the data read and write process is retried, the number of retries increases by performing the data read and write process while varying parameters related to the data read and write process with a fixed flying height of the magnetic head, and occasionally, the data read and write process fails.